Shellen is an interactive shellcoding environment. If you want a handy tool to write shellcodes, then shellen may be your friend. Shellen can also be used as an assembly or disassembly tool.
keystone and capstone engines are used for all of shellen's operations.
Shellen only works on python3. python2 support may appear in the future.
First, you should install shellen's dependencies:
$ sudo apt-get install cmake python3-dev python3-setuptools
You can install the stable version of shellen using
$ sudo pip3 install shellen
Or if you already have all required packages (see Requirements):
$ python3 setup.py install
If you have any problems with installing keystone-engine, then you should compile keystone-engine (see the COMPILE.md file in the keystone repository)
How to Run Shellen
After installing shellen and its required packages, you can run shellen by typing the following in your terminal:
You can run shellen's
help command to get information about shellen's usage.
Shellen assembles and disassembles instructions, so there are two usage modes: asm and dsm respectively. There are other features which include searching syscall tables and searching for common shellcodes.
Shellen has a useful prompt that displays the current mode, OS (operating system for syscalls), and the current mode's chosen architecture. Shellen's prompt looks like this:
You can edit your input like you're typing in a terminal. Also, shellen records your command history (just type your up arrow to see your previous commands).
L is the shortened name of
Linux in the prompt. Below listed all other OS names:
If you want to change OS, then type
setos [linux/windows/macos] as follows:
L:asm:x86_32 > setos windows [+] OS changed to windows.
To change current mode, enter
dsm in the prompt.
L:dsm:arm32 > asm [+] Changed to asm (assembly) mode L:asm:x86_32 > dsm [+] Changed to dsm (disassembly) mode L:dsm:arm32 >
||Clear the terminal screen. As usual
||Show the help message.|
||Finish the current session and quit|
To assemble instuctions, type them and separate them with semicolons as shown here:
L:asm:x86_32 > mov edx, eax; xor eax, eax; inc edx; int 80; [+] Bytes count: 7 Raw bytes: "\x89\xc2\x31\xc0\x42\xcd\x50" Hex string: "89c231c042cd50"
If your assembled bytes contain a null byte, then shellen will tell you about this.
Disassembling is similar to assembling. Instead, type your bytes in the prompt and see the result!
L:dsm:x86_32 > 89c231c042cd50 0x00080000: mov edx, eax 0x00080002: xor eax, eax 0x00080004: inc edx 0x00080005: int 0x50
Also, you can run your shellcode in a subprocess. Be aware that this can harm your system!. Jump to the last shellcode in a subprocess. What could go wrong?' Note that you don't get to control the base address your code gets loaded at, and this assumes that the instructions will make sense to your CPU. See
shellen to see how to use it.
I'm planning to execute subprocess in a some virtual environment in order to make it safer to run potentially dangerous shellcode.
dsm modes work for different architectures. To see a list of available architectures for shellen's current mode, type this:
L:dsm:x86_32 > archs ┌────────┬────────┬─────────┬─────────┬────────┐ │ │ │ │ │ │ │ arm32 │ mips32 │ sparc32 │ systemz │ x86_16 │ │ arm64 │ mips64 │ sparc64 │ │ x86_32 │ │ arm_tb │ │ │ │ x86_64 │ └────────┴────────┴─────────┴─────────┴────────┘
If you want to change the current architecture, enter the following:
L:dsm:x86_32 > setarch arm32 [+] Architecture of dsm changed to arm32
When you create a shellcode, you will need syscalls. To lookup syscalls with shellen, type
sys and the name of your desired syscall. Shellen will produce a list of syscalls which may contain the syscall you were looking for.
L:asm:x86_32 > sys open ┌────────┬───────┬──────────────────────┬──────────────────────┬──────────────┬──────────────┐ │ name │ eax │ ebx │ ecx │ edx │ esi │ ├────────┼───────┼──────────────────────┼──────────────────────┼──────────────┼──────────────┤ │ open │ 0x05 │ const char *filename │ int flags │ umode_t mode │ - │ │ openat │ 0x127 │ int dfd │ const char *filename │ int flags │ umode_t mode │ └────────┴───────┴──────────────────────┴──────────────────────┴──────────────┴──────────────┘
sys prints a list of possible variants for the provided syscall. The syscall table that shellen searches depends on the chosen architecture and operating system (OS). In this case, the architecture is
x86_32 and the OS is
Shellen can show you a list of common shellcodes depending on your keyword. Shellen's keyword lookup uses shell-storm.org's API (thanks to the author!) and can be used like this:
L:asm:x86_32 > shell <keyword> <count>
count parameter isn't required. There is an image of
shell <keyword> <count>'s output in the Pictures section.
Supported Operating Systems
Currently, shellen is only supported on Linux. If you want to add functionality for Windows or MacOS, then write an issue and I will add support.
How to Report Problems or Request for New Features
If you find a problem/bug or something, write an issue about this problem. Also, if you think that a feature will be a nice addition to shellen, do the same -- write an issue and I will try to add your requested feature.
- Syscalls lists
- Database of common shellcodes
- Add ROP builder
- Add editing an assembly code in multiple lines
- Different histories for
- Virtual environment to run shellcodes
Just a little bunch of pictures. (They are outdated because of adding different features)